lean4-htt/src/kernel/instantiate.cpp
Leonardo de Moura 190855ad1b Add (relaxed) version of instantiate that can substitute terms containing free variables
Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
2013-08-03 16:12:15 -07:00

44 lines
1.2 KiB
C++

/*
Copyright (c) 2013 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#include <algorithm>
#include "free_vars.h"
#include "replace.h"
namespace lean {
expr instantiate_with_closed(unsigned n, expr const * s, expr const & e) {
lean_assert(std::all_of(s, s+n, closed));
auto f = [=](expr const & e, unsigned offset) -> expr {
if (is_var(e)) {
unsigned vidx = var_idx(e);
if (vidx >= offset) {
if (vidx < offset + n)
return s[n - (vidx - offset) - 1];
else
return var(vidx - n);
}
}
return e;
};
return replace_fn<decltype(f)>(f)(e);
}
expr instantiate(unsigned n, expr const * s, expr const & e) {
auto f = [=](expr const & e, unsigned offset) -> expr {
if (is_var(e)) {
unsigned vidx = var_idx(e);
if (vidx >= offset) {
if (vidx < offset + n)
return lift_free_vars(s[n - (vidx - offset) - 1], offset);
else
return var(vidx - n);
}
}
return e;
};
return replace_fn<decltype(f)>(f)(e);
}
}